DE102008064408A1 - Pilot operated valve and valve controlled hydraulic machine - Google Patents

Abstract

Disclosed are a pilot-operated valve with an electromagnetically actuated pilot control and a valve-controlled hydraulic machine with such a valve. According to the invention, in addition to an armature of the electromagnetically actuated pilot control, a further main stage armature is provided, via which a valve body of the main stage for opening a pressure fluid flow path can be moved into an open position.

Description

The The invention relates to a pilot operated valve according to Preamble of claim 1 and a valve-controlled hydraulic machine with such a valve.

Such valve-controlled hydraulic machines are for example from the EP 1 537 333 B1 known. This document shows a hydraulic machine in axial or radial piston construction, which can be operated as a motor as well as a pump, wherein the delivery or absorption volume via the valve control is almost infinitely adjustable. In one embodiment, the hydraulic machine is designed as an axial piston machine, wherein a plurality of piston arranged in a cylinder is supported on a rotatably mounted swash plate. Each of these pistons defined with the associated cylinder chamber a working space, which is connectable via a low-pressure side valve and a high-pressure side valve with a pressure medium inlet or a pressure medium drain. In the known solution, the two valves are designed as electrically unlockable or lockable check valves, which can be controlled via the pump control and operate in the respective working space in "full mode", "partial mode" or "idle mode". As a result, the delivery or displacement volume can be adjusted continuously from a maximum value to zero. Via a control unit, the hydraulic machine is operated according to a control algorithm in order to achieve the lowest possible pulsation sum flow volume (pump) or total displacement volume flow (motor). The volume flow adjustment is often carried out after a phase control, but it can also be performed after a Phasenabschnitts- or phase cut control.

hydraulic machines with variable via the valve control intake / displacement Also called Digital Displacement Units (DDU). In such Hydromachines are basically all positive displacement principles conceivable. However, piston engines are advantageous, in particular in Radial piston construction, as these make it possible to and output separately for each displacer and thus actively controlling. It can make sense to distinguish between pump and motor operation, so that then the control element for the low or high pressure connection can look different.

Such a control element is for example in the WO 2008/029073 A1 described. This document shows a high-pressure side valve, which is designed with a pilot control. This valve has a main stage with a valve body biased against a valve seat. The valve body is penetrated by a pilot control hole, which is closed in a basic position by a pilot valve body, which is also the armature of an electromagnetic pilot actuator. When energizing this actuator, the pilot valve body performs a stroke and opens the pilot hole, so that the valve body is relieved in the closing direction and can be lifted by the pressure at the entrance of his valve seat. The stroke of the valve body corresponds approximately to the stroke of the pilot valve body / armature.

At Such a high-pressure side valve will be different, sometimes set conflicting requirements. One in view Hydromachine minimized to the installation space begins in its overall dimensions small valve with the largest possible and thus low-resistance flow cross-section ahead. Such a thing however, a large flow cross-section requires one greater valve lift, which is the demand for higher Valve dynamics with the lowest possible electrical power consumption contradicts. On top of that, the requirements for the valve vary with different operating points of the hydraulic machine. From high speeds, for example, arise large Volume flows and demands for short switching times with low speeds go long duty cycles for accompanied by the magnetic coils.

In contrast, The invention is based on the object, a pilot operated valve and to provide a hydraulic machine running thereby, the minimal installation space, even for large volume flows is suitable and still a high valve dynamics for driving the hydraulic machine guaranteed.

These Task is performed by a pilot operated valve with the characteristics of Patent claim 1 or by a valve-controlled hydraulic machine solved with the features of the independent claim 11.

According to the invention the pilot operated valve with a main stage and an electromagnetically actuated Pre-control executed, the main stage a valve body has, which is interspersed by a pilot flow path. This is by means of a pilot valve body of a pilot actuator lockable, wherein a stroke of an armature of this Vorsteueraktors indirectly or directly transferable to the pilot valve body is. According to the invention is in addition to the anchor associated with the pilot valve body another Main stage anchor provided after a partial lift of the valve body comes into electromagnetic operative engagement to this in a Endhubbereich to move and / or keep there.

In other words, by the anchor the pilot actuator, the pilot valve body is moved only with a comparatively small lift, which is required to control the pilot flow path. After relieving the valve body of the main stage in the closing direction of the valve body also performs a corresponding to the stroke of the pilot valve body partial stroke. In this case, then the second main-stage armature comes into operative engagement, so that the valve body performs a further stroke and is kept open in Endhubbereich. Ie. In this solution, two successive or overlapping effective anchor associated with a magnetic circuit, which cause the valve body performs a comparatively large stroke, so that the valve can be used even with relatively large pressure medium flow rates, without acting in the flow in the closing direction effective flow forces , As a result, the hydraulic machine designed with the pilot-operated valve according to the invention can be operated with high dynamics in engine operation at higher rotational speeds than the conventional solution.

at a variant of the invention, the valve body of the main stage a valve plate biased against a valve seat and in the pilot valve body at least in sections and against a pilot seat of the pilot flow path is biased.

These Preload can be done for example via a tension spring, which is supported on the valve plate.

at such a variant, the valve disc, for example, a Guide bush on which the tension spring is supported is.

at an embodiment is in addition to the Tension spring a switching spring provided, which the pilot valve body biased against the pilot valve seat.

at A variant of the invention is the armature of the pilot actuator of a guide rod of the pilot valve body interspersed, which carries at its end portion a spring plate, on which the aforementioned switching spring is supported, the also biased mainstay anchor towards his basic position.

there is then preferably the main stage anchor to the valve body attached or integrally formed with this.

there For example, the valve body with a back Hub projection to be executed on the precursor anchor is attached.

to Characteristic adaptation can be at one anchor to another anchor outwardly extending projection are formed in the aforementioned Endhubbereich dips into a corresponding recess of the other anchor, so that the magnetic force on the anchor at a comparatively small stroke is enlarged.

To the Avoid sticking the second anchor to the first anchor can between these a Antiklebeplättchen or a paramagnetic Coating be provided so that the closing time of the valve is minimized. Likewise, a guide bush protrude from the valve body in the direction of the pilot control armature and thus act as Antiklebeflättchen. This is the Guide bush made of paramagnetic material.

other advantageous developments of the invention are the subject of further Dependent claims.

in the Below is a preferred embodiment of Invention explained in more detail with reference to schematic drawings. Show it:

1 a longitudinal section through an inventive pilot-operated valve, which can be used as a high-pressure side valve of a valve-controlled hydraulic machine;

2 shows the pilot operated valve 1 with open pilot control and

3 the valve off 1 with the main level open.

1 shows a longitudinal section through a valve that can be used for example as a fast-switching electrically unlockable high pressure valve of a DDU of the type described above. Such a high pressure valve 1 serves to control the high-pressure side inlet and outlet of the DDU. During pump operation, the high pressure valve operates as a conventional spring-loaded check valve. During engine operation, it must be actively opened against the upcoming high pressure in order to release the pressure medium inflow to the displacement chamber.

The illustrated high pressure valve 1 is designed as a cartridge valve that can be screwed into a receiving hole of the DDU or the hydrostatic displacement unit. Here, the radial port A with a high-pressure channel and the axial port B with a displacement of the hydraulic machine is in fluid communication.

The high pressure valve 1 is designed as a pilot operated valve and has a main stage 2 that's a feedforward 4 assigned.

The main stage 2 has a seat bush 6 at which the radial port A formed by a radial bore star and the axial port B are formed. At an axial bore 8th the seat bush 6 is a valve seat through a radial shoulder 10 formed, against the in the illustrated basic position of the high pressure valve 1 a valve body 12 is biased. This consists essentially of a valve disk 14 , the front side with a seat 16 is executed, which in the basic position sealingly against the valve seat 10 is applied. The valve plate 14 has a turn in 1 down, out of the axial bore 8th out extending projection 18 that of a pilot hole 20 is interspersed, which is in 1 upwards to a pilot valve seat 22 extended. Against this is a pilot valve body 24 biased, whose structure will be explained in more detail below.

According to 1 is the valve plate 14 at his from the valve seat 10 opposite side downgraded via a radial shoulder, so that the valve plate 14 in a rear hub ledge 26 of the valve body 12 passes. The pilot hole 20 is in the radially expanded area of the valve disk 14 and to the hub projection 26 towards the radial direction to a guide hole 28 extended, in the back of a guide bush 30 is used. This can be made of paramagnetic material and axially slightly above the back face of the hub projection 26 survive and thus serve as Antiklebeplättchen.

In the area of this guide bush 30 is on the outer circumference of the hub projection 26 a mainstay anchor 32 placed. In the illustrated embodiment, the material of the main stage anchor 32 designed for optimum magnetic flux while the spring plate 14 with regard to an optimized sealing effect and wear resistance is designed.

The attachment of the main level anchor 32 on the hub projection 26 can be done in any way, for example, by shrinking, welding, screwing or otherwise. In the illustrated embodiment, the main stage anchor 32 plate-shaped with one in 1 upwardly axially projecting peripheral edge 34 executed.

The axial guidance of the valve body 12 in the seat bush 6 occurs along the outer peripheral surfaces of the main stage anchor 32 and the spring plate 14 - These sections are sliding along an inner guide 36 the seat bush 6 guided.

According to 1 is the seat bushing 6 in a valve sleeve 38 used, which is screwed into the receiving bore of the hydraulic machine mentioned above.

In the distance to the pilot valve seat 22 is the pilot valve body 24 the pilot control 4 to a leadership alliance 40 extended, in the guide hole 28 is guided axially displaceable. Following the leadership association 40 is the pilot valve body 24 in the radial direction to a guide rod 42 downgraded via the guide bush 30 is guided.

At the in 1 upper annular face of the guide collar 40 grips a tension spring 44 which, in turn, on the adjacent annular face of the guide bushing 30 is supported, so that the pilot valve body 24 with its conical tip sealing against the pilot valve seat 22 is biased.

As shown in 1 extends the guide rod 42 upwards over the guide bush 30 out and interspersed an anchor 46 the pilot control 4 , Stand out from this anchor 46 extending end portion of the guide rod 42 is a bush-shaped, stepped spring plate 48 placed on which a switching spring 50 attacks. An in 1 bottom annular face 52 of the spring plate 48 lies on a stop surface 54 of the anchor 46 on, so that this by the bias of the switching spring 50 with a radially projecting stop lug 56 on the outer circumference of the anchor 46 against a flush on the adjacent end face of the seat bushing 6 patch washer 58 is biased. The anchor 46 is at its the mainstay anchor 32 assigning end face with an annular recess 57 whose geometry conforms to the dimension of the projecting peripheral edge 34 of the main level anchor 32 is adjusted.

In a receiving hole 60 the valve sleeve 38 is a bobbin 62 consisting of a coil carrier and a winding, inserted by means of an electrical connection 64 energized to the anchor 46 to press. The bobbin 62 is upwards on a pole ring 66 and down through another, conical and non-magnetizable cone ring 68 supported. The function of this cone ring 68 is to seal the high pressure area to the spool and further to the valve environment. Furthermore, the magnetic flux passes around the cone ring 68 around, so that the field line according to 3 established. These construction elements assume approximately the function of a pole tube. In the from the pole ring 66 and the cone ring 68 and from the bobbin 62 defined interior is an axial pole piece 70 used at his in 1 lower end portion is flared and on the corresponding executed cone ring 68 lies flat and this off engages in sections. The outer circumference of the cone ring 68 lies with an inclined surface on a corresponding inclined shoulder 72 the valve sleeve 38 on, so that the assembly consisting of the pole piece 70 and the cone ring 68 upwards ( 1 ) is secured. The axial securing in the opposite direction is done by a face plate 74 , which has a fixing screw 76 with the axial pole piece 70 is connected and in the axial direction of the adjacent annular end face of the pole ring 66 supported. This is in turn with a support shoulder 80 on a shoulder 78 the valve sleeve 68 supported so that the entire pilot control in the valve sleeve 38 is tense.

The pole piece 70 is with a blind hole 82 executed, at the end face of the switching spring 50 is supported and in the illustrated in the basic position of the spring plate 48 and the end portion of the guide bar 42 dive in sections.

In the illustrated basic position, in which the spring plate 14 on the valve seat 10 sits up and the anchor 46 against the washer 58 is biased, the peripheral edge emerges 34 of the main level anchor 32 not at all or only slightly into the annular recess 57 of the anchor 46 one, leaving a secondary working air gap 59 between the anchors 32 . 46 remains. Between the upper ( 1 ) Anchor face of the anchor 46 and the adjacent end face of the pole piece 70 there remains a pilot working air gap 21 , Here is the valve disk 14 practically by the force of the switching spring 50 against the valve seat 10 biased, the force of the switching spring 50 via the pilot valve body 24 on the valve plate 14 is transmitted.

In pump operation works the above-described high pressure valve 1 as a check valve, by the pressure in the displacement chamber (port B) against the force of the switching spring 50 can be opened. In the engine operation described above, the higher pressure is applied to the radial port A, so that the high pressure valve 1 must be opened against this high pressure. This case is described below on the basis of

2 and 3 explained. The cuts in the 2 and 3 are slightly different than in the presentation according to 1 chosen - but this does not matter for the above explanations. From this other intersection becomes clear that the two anchors 46 . 32 each through axially parallel relief holes 86 . 88 pressure balanced.

When energizing the magnetic coil of the bobbin 62 becomes the anchor 46 as shown in 2 moved upwards, so that the pilot working air gap 21 closes. It takes the anchor 46 over the spring plate 48 the guide rod 42 with, so in the valve plate 14 the pilot valve body 24 from the pilot valve seat 22 takes off.

By lifting the pilot valve body 24 from the pilot valve seat 22 a pilot control flow path between the two ports A, B is opened. This pilot flow path is shown in FIG 1 indicated by dashed lines and with the reference numeral 82 characterized. Accordingly, in the circumferential wall of the hub projection 26 and in the leadership alliance 40 Holes provided, the control oil flow from port B via the open pilot valve seat, through the guide collar 40 through and in the radial direction through the hub projection 26 to enable connection A.

By lifting the pilot valve body 24 becomes the tension spring 44 cocked, causing over the guide bush 30 one in the opening direction on the valve plate 14 effective force is transmitted.

The valve plate 14 however, does not immediately lift from its valve seat after opening the above pilot flow path 10 but only when the pressure level between the high pressure side and the low pressure side (displacement) is almost balanced and thus in the closing direction as a result of the pressure difference across the valve disk 14 effective force is smaller than the force acting in the opening direction of the tension spring 44 ,

If the anchor 46 at the pole piece 70 is applied, the magnetic circuit is split, where due to the not shown, via the main stage anchor 34 extending part of the magnetic circuit already has an opening force on the main stage anchor 34 acts.

After the aforementioned pressure equalization of the valve plate 14 as in 3 represented by the force of the tension spring 44 from the valve seat 10 lifted off, in which case the main level anchor 34 continues to come into operative engagement with the magnetic field of the solenoid so that then the main stage anchor 34 is completely in the magnetic flux (see 3 ). The stroke of the spring plate 14 is then electromagnetically assisted, so that this performs a comparatively large stroke and in the illustrated position, in which the main stage anchor 34 to the anchor 46 is held in its open position - the secondary air gap 59 is then closed. With variation of the regulated current level, the closing and holding force can be adapted to the operating point of the hydraulic machine. It is preferred if the axial length of the pilot air gap 74 less than the opening stroke H of the valve disk 14 is. Ie. the guide rod 42 will be with him inventive principle only as far as it moves the pilot control fluidically requires. The actual opening stroke is essentially due to the force of the electromagnet, wherein this opening stroke can in turn be adapted to the pressure and pressure medium volume flow conditions, so that closing of the high-pressure valve due to flow forces is practically impossible.

Depending on the version of the main level anchor 32 can the valve body 12 even in valve base position be partially involved in the magnetic flux. Thus, the beginning of the movement is already supported by the magnet. This allows the tension spring 44 be performed weaker. However, this is at the expense of the magnetic force at the anchor 46 and thus at the expense of the achievable opening force of the pilot control.

Basically, so can on the geometric design of the main level anchor 32 the magnetic force between pre-control and main stage are distributed.

As the valve plate 14 fluidically conditionally executes a larger stroke H than the guide rod 42 , this must be during the stroke of the valve disk 14 relative to the anchor 46 be movable. During this relative movement, the switching spring 50 compresses and thus holds the restoring force of the valve 1 in front. The compression work of the switching spring 10 essentially results from the magnetic circuit.

In the illustrated embodiment, the valve body 12 two-piece with the valve plate 14 and the main level anchor 34 constructed, the latter being made of a magnetically favorable material. In principle, however, the valve body can also be formed in one piece.

During the above-described stroke H of the valve disk 14 the peripheral edge emerges 34 of the main level anchor 34 in the corresponding ring recess 57 of the anchor 46 the pilot control, before the two facing each other end faces of the two anchors 46 . 34 get into contact. Due to the geometry of the peripheral edge 34 and the corresponding recess 57 can change the characteristic of the main level anchor 34 Acting magnetic force can be adapted to the particular conditions. Of course, in kinematic reversal, a projection on the anchor 46 be provided, which in a corresponding recess on the main stage anchor 34 dips. Depending on the characteristic curve adaptation, the projections may have different geometries. In principle, it is also possible to form an axial projection on one of the armatures, which dips into a corresponding axial recess of the other armature, this projection, for example, can be cylindrical or trapezoidal and the corresponding wall regions of the other armature can then be bevelled. Instead of the ring-cylindrical peripheral edge 34 Of course, other geometries, for example, a peripheral edge with triangular or trapezoidal cross-section can be selected - in principle, the overlap region can be chosen so that the characteristic is suitably adapted to the respective desired conditions.

To stick the two anchors 46 . 34 to each other or the anchor 46 at the pole piece 70 To avoid, in the respective investment areas still an anti-adhesive tiles are provided.

Disclosed are a pilot operated valve with an electromagnetically operated Pilot control and a valve-controlled hydraulic machine with such Valve. According to the invention, in addition to an anchor the electromagnetically actuated pilot control yet another main stage armature provided, via which a valve body the main stage for opening a pressure fluid flow path is movable in an open position.

1

High pressure valve

2

main stage

4

feedforward

6

seat bushing

8th

axial bore

10

valve seat

12

valve body

14

valve disc

16

seat

18

head Start

20

pilot hole

22

Pilot valve seat

24

Pilot valve body

26

hub projection

28

guide bore

30

guide bush

32

Main stages anchor

34

circumferential edge

36

inner guide

38

valve sleeve

40

guide collar

42

guide rod

44

tension spring

46

anchor

48

spring plate

50

switching spring

52

Annular face

54

stop surface

56

stop lug

57

annular recess

58

washer

59

Secondary air gap

60

location hole

62

bobbins

64

connection

66

pole ring

68

cone ring

70

pole piece

72

angular contact

74

faceplate

76

fixing screw

78

shoulder

80

supporting shoulder

82

Pilot fluid path

84

Pilot air gap

86

relief well

88

relief well

90

field line

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1537333 B1 [0002]
• - WO 2008/029073 A1 [0004]

Claims (11)

Pilot operated valve with an electromagnetically actuated pilot control ( 4 ), one main level ( 2 ) a valve body ( 12 ) derived from a pilot flow path ( 82 ) penetrated by a pilot valve body ( 24 ) which can be closed by means of a pre-tax factor ( 62 . 24 ) with an anchor ( 46 ) can be brought from a closed position into an open position, characterized by a main stage anchor ( 32 ), which after a partial lift of the valve body ( 12 ) comes into operative engagement with the pilot actuator to the valve body ( 12 ) to move and / or hold in a Endhubbereich. Valve according to claim 1, wherein the valve body ( 12 ) a valve disk ( 14 ), which against a valve seat ( 10 ) is biased and in which the pilot valve body ( 12 ) is guided in sections and against a pilot valve seat ( 22 ) of the pilot flow path ( 82 ) is biased. Valve according to claim 2, wherein the bias of the pilot valve body ( 24 ) via a tension spring ( 44 ) carried out on the valve body ( 12 ) is supported. Valve according to claim 2 and 3, wherein the valve body ( 12 ) a guide bush ( 30 ), on which the tension spring ( 44 ) is supported. Valve according to one of the preceding claims, wherein the valve body ( 12 ) via a switching spring ( 50 ) in the direction of its valve seat ( 10 ) is biased. Valve according to claim 5, wherein the armature ( 46 ) of a guide rod ( 42 ) of the pilot valve body ( 24 ) is penetrated, which at its end portion a spring plate ( 48 ), on which the switching spring ( 50 ) which also attacks the anchor ( 46 ) is biased toward a home position. Valve according to one of the preceding claims, wherein the main stage anchor ( 32 ) to the valve body ( 12 ) is set. Valve according to claim 7, wherein the valve body ( 12 ) a rear hub projection ( 26 ), to which the main level anchor ( 32 ) is attached. Valve according to claim 8, wherein at an anchor ( 32 . 46 ) to the characteristic curve adaptation to the other anchor ( 46 . 32 ) extending projection ( 34 ) is formed in the Endhubbereich in a corresponding recess ( 57 ) of the other anchor ( 46 . 32 immersed). Valve according to claim 9, wherein in the contact area the armature ( 32 . 46 ) is provided to each other or to other components a Antiklebeplättchen. Valve controlled hydraulic machine with a variety of actively controllable displacer units, respectively a piston which defines a displacement chamber, each over a controllable by means of a control unit high-pressure side Valve with a high pressure line and a controllable Low pressure side valve with a low pressure line connectable is characterized by a high pressure valve according to a of the preceding claims.